Spark plug shield and cooler



Oct. 12, 1937. R. CHILTON ET Al.

SPARK PLUG SHIELD AND COOLER Filed June 9, 1954 .,...mllil I l l l r u F 3 lNv'ENToRs ROLAND CHI/JUN "@RI/oLPf/.' 6:46a.

Patented Oct. 12, 1937 UNITED STATES PATENT OFFICE SPARK PLUG SHIELD AND COOLER Application June 9, 1934, Serial No. 729,774

' 5 claims.'

This invention relates to the electrical shielding of internal combustion engine spark plugs against radio interference and provides improved means for cooling the spark plug and the adjacent cylinder wall, particularly in relation to air-cooled finned cylinders.

Patents Nos. 1,914,940 and 1,910,951 (screwedin spark plug cooler and integral spark plug cooler) disclose a finned cylindrical extension of the cylinder surrounding the spark plug.

While these inventions have gone into extensive use, further experimentation has shown that, with certain types of spark plugs, ventilation whereby air is allowed to impinge on the plug will further reduce its temperature and that, if the ventilation openings be surrounded by extended metallic walls, the shielding effect is still adequate.

According to the provisions of this invention, the cylinder head fins themselves comprise shielding whereby well grounded metal walls extend outwardly from each spark plug opening.

In the drawing:

Fig. 1 is a fragmentary plan view of a cylinder head incorporating the provisions of this invention; y

Fig. 2 is an elevation; and

Fig. 3 is a fragmentary sectional view.

In these iigures,'l0 designates a cylinder head from which a substantially unfinned intake rockwhich a spark plug shielding cap I8 may be seat-- ed. Beneath this ring the fins Il are interrupted for the minimum amount necessary for the insertion of the spark plug bushing I2 and the plug so that a maidmum number of high ns are effective close to the plug. The ns are preferably rather closely spaced and are of substantial depth whereby a considerable number of fins embrace the spark plug and extend outwardly along a considerable portion of the plug length.

By `the disposition disclosed it may be seen that in addition to their normal function of cooling the general surface of the head, the fins act as air conduits which conduct the air flow over the head so that it ixnpinges upon and cools the 'spark plus. v

Due to the relatively great amount of metal comprised in the ilns which extend fr'm the cylinder around each spark plug opening, radio interference is suppressed, the effectiveness in this connection being enhanced by the perfect grounding of each fin to the headby virtue of the preferred integral construction of the head and fins. 5

The drawing shows the use of the detachable cap I8, as disclosed in a copending application, Serial No. 472,040, whereby the exposed terminal of a normal spark plug is adequately shielded. However, if it is desired to use plugs wherein the 10 shielding is incorporated integrally, the cap I8 may be deleted and the ignition wire attached directly to the shielded plug.

It will be seen that by the provisions of this invention adequate ventilation of the plug is com- 15 bined with effective radio shielding, while at the same time a large and effective iin area is provided in close proximity to the plug in order to take care of the high rate of heat generation Within the cylinder at this point.

While we have described our invention in detail in its present preferred embodiment, it will be obvious to those skilled vin the art, after understanding our invention, that various changes and modifications may be made therein without 25 departing from the spirit or scope thereof. We aim in the appended claims to cover all such modifications and changes.

What is claimed is:

1. The combination with an engine cylinder of a spark plug secured in the wall of the cylinder,

a plurality of integral cooling fins terminating adjacent the plug and a ring surrounding the plug at the top only of said fins, the fins, ring and cylinder wall defining a plurality of ventilation slots for said plug, said plug being electrically shielded by said ilns. I

2. The combination with a cylinder head having a spark plug extending therefrom, of cooling ilns, a' ring embracing the upper end only of 40 said plug carried by certain of said fins, forming ducts between said fins for conducting cooling air tosaid plug and further comprising means for electrically shielding said plug.

3. The combination in a nned air-cooled cylinder having a. spark plug opening therein, of a ring of less depth than the depth of. said ns integral with the outer edges of certain of said fins., said ring being coaxial with the plug opening, the continuity of said fins within the embrace of said ring being interrupted to permit the insertion of a spark plug within said opening.

4. The combination with an engine cylinder head, of a plurality of substantially parallel cooll ing ns extending from the head, certain of said ns being interrupted to provide a spark plug well, said cylinder having a plug opening coaxial with said well, and a relatively narrow reinforcing ring integral with said interrupted ns at the outer edges thereof only, whereby air conducting ducts are formed between said fins and below said ring to permit the impingement of cooling air on a plug inserted within. said cylinder opening.

5. The combination with a cylinder head having a spark plug extending therefrom, o a plurality of cylinder cooling ns integral with said cylinder, certain of said fins being interrupted plug. and a metallic ring joining said interrupted f n ends toward the outer part only of said well.

ROLAND CHILTON'. RUDOLPH. F. GAGG. 

